Laser Distance Measurement System Based On 1.5?m

Compared with other types of light, laser has many advantages. It is widely used in the fields of industry, aerospace, military, atmospheric detection and machine technology. Thus, the laser ranging technology is of great significance in the construction of national economy and national defense. With the development of laser technology, the types of lasers are also becoming more and more diverse, lasers which possess various wavelengths and generation modes have emerged. Reducing its volume and improving the security effectively is the development trend of laser ranging equipment.In this paper, we mainly study the long-distance laser ranging system emitting laser with a wavelength of 1.5?m. The most remote distance of the system can reach to more than 1 000 meters. The ranging accuracy of this system can reach to meter level. This paper uses the pulse ranging method so that the laser ranging system can also measure the long distance target without the corporate target. The system mainly consists of three parts, including laser emission module, laser receiving module and FPGA information processing module. This paper mainly focuses on the laser receiving module and FPGA information processing module. The laser receiving module is mainly to amplify the weak current generated by the photodiode without distortion and identify the moment of the echo pulse amplified. The timing discrimination circuit adopts the method of constant proportion, which can effectively eliminate the error caused by the change of pulse amplitude. The main function of signal processing part is to measure the laser flying time and convert it into distance. This part make use of the frequency multiplication and phase shift of PLL which is internal in FPGA. Furthermore, it uses the method of multi clock timing to improve the measurement accuracy. In this paper, a delay filter detection method is proposed. That is, only when the echo signal reaches a certain pulse width, the echo signal is considered to be effective, which will effectively reduce the misjudgment caused by the noise, reducing false alarm. At last, the practical ranging experiment is carried out on the entire system. In the experiment, the method of calibration distance is used to analyze the relative error of ranging performance.